The iBooks update announced earlier today is now out. The update includes:

• See all your iBookstore purchases in iCloud—right on your bookshelf with iOS 6
• Scroll vertically through your books with the flick of a finger using the new Scroll theme
• Receive free updates to purchased books—including new chapters, corrections, and other improvements
• Look up definitions for words in German, Spanish, French, Japanese and Simplified Chinese with iOS 6
• Share quotes or thoughts about your favorite book with friends on Facebook, Twitter, Messages, or Mail